Device for monitoring a tubular belt conveyor system

ABSTRACT

The invention relates to a device for monitoring a tubular belt conveyor system, comprising the following: a conveyor belt consisting of an elastomeric material, especially with embedded tie rods, the conveyor belt being closed to form a tubular belt by overlapping its longitudinal edges so as to form an overlap area; other system parts, i.e., a driving drum, a tail pulley, support rollers, guide rollers, supporting structures and optionally, other parts. The inventive device is characterized in that the device for monitoring the overlap area of the tubular belt is provided with an optoelectronic system. In the event of a deviation from the desired conveyor belt overlap, the optoelectronic system initiates a correction of position by means of the guiding rollers. If the corrective measures are not taken within a certain period, the tubular belt conveyor system is automatically disconnected.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. §119 of German Application No.199 29 580.8 filed Jun. 29, 1999. Applicant also claims priority under35 U.S.C. §120 of PCT/DE00/01959 filed Jun. 15, 2000. The internationalapplication under PCT article 21(2) was not published in English.

DESCRIPTION

The invention relates to a device for monitoring a tubular belt conveyorsystem comprising the following:

a conveyor belt consisting of an elastomeric material, particularly withembedded tie rods, whereby the conveyor belt can be closed so as to forma tubular belt by overlapping its longitudinal edges to form an overlaparea; as well as

other system components such as a driving drum, a reversing drum,support rollers, guide rollers, supporting structures, as well as otheroptional components, if need be.

Tubular conveyor belts (pipe conveyor belts for encapsulated conveyance)are predominantly employed where bulk material has to be conveyed in arelatively confined space through horizontal and vertical curves.

Such conveyor systems have been used in the last few years also forconveying material over distances longer than 1 kilometer by virtue oftheir special adaptability to the topographical conditions.

In addition to their adaptability to the terrain, the advantages offeredby tubular belts include the protection of the transported materialagainst environmental influences (rain, wind, etc.) and the protectionof the environment against material dropping from the conveyor belt(ashes from power plants; gypsum etc.).

Problems arise in connection with the operation of tubular conveyorbelts with the guidance of the overlapping parts of the belt. Thesupport and guide rollers of the system are responsible for correctlyrunning the tubular conveyor belt (DE-C-31 22 664). Said rollers areindividually aligned depending on the course the conveyor system isrunning.

The function of said rollers is influenced by varying weather andtemperature conditions and by the wear, as well as by design defects.

Moisture, for example, reduces the value of the friction between theroller and the conveyor belt, which results in guidance that is notoptimal.

The tubular belt is opened for loading and unloading, i.e. it is driveninto a horizontal position. If the area of overlap of the tubular belthas not been guided into the correct position, i.e. if said overlap areais located at the bottom instead of at the top, for example as it isrunning up on the ejecting drum, the conveyor belt will be folded or itwill run off of the drum sideways. Both events lead to substantialdamage to the tubular conveyor belt and have to be absolutely avoidedfor that reason.

Said problem has been solved until now by forcibly guiding the conveyorbelt over finger rollers projecting into the cross section of thetubular belt (DE-C-34 17 718), among other measures. Said method issuccessful in most cases; however, it is afflicted with the substantialdrawback that the conveyor belt is attacked and damaged by the fingerrollers. Said method consequently does not represent any satisfyingpermanent solution.

Now, a device for monitoring a tubular conveyor belt system isintroduced in laid-open patent specification DE-A195 22 757, whichemploys detectors specifically in the form of the two followingvariations:

The conveyor belt is provided on its outer side with a detectable colormarking. This, however, requires that the surface marking will not bedamaged or soiled, which, however, cannot be avoided in most cases. Theresult will then be that the system is no longer capable of fulfillingits function, or satisfying it only to a limited extent.

The conveyor belt comprises detectable integrated indicators inparticular in conjunction with steel cable belts, whereby individualcables or cords are replaced by the indicator. The drawback in this caseis that the behavior of the tie rods of the conveyor belt might beadversely affected.

Therefore, the problem of the invention is to provide a conveyor systemthat excludes the drawbacks described above. Furthermore, the aim isthat the system can be employed for all types of conveyor belts (steelcable conveyor belts, textile conveyor belts, aramide conveyor belts),as well as for all kinds of different conveyor constellations (curves,uphill gradients etc.), namely under the aspect of encapsulatedconveyance. Moreover, the aim is that the conveyor system is free ofwear, low in maintenance, and economical with as little technicalexpenditure as possible.

Said problem is solved according to the characterizing part of claim 1in that the device for monitoring the overlap area of the tubular beltis provided with an optoelectronic system which, in the event thedesired overlap of the conveyor belt is deviating, initiates acorrective setting by means of the guide rollers or, if the correctivemeasures are not successful within a preset period of time,automatically effects the shutdown of the tubular belt conveyor system.

Useful variations of the invention are specified in claims 2 to 11.

The invention is now explained in the following with the help ofexemplified embodiments and by reference to schematic drawings, inwhich:

FIG. 1 is a top view of a tubular belt conveyor system with closed andopen sections.

FIG. 2 is a top view of a tubular belt with the overlap area in thenormal position.

FIG. 3 is a top view of a tubular belt with the overlap area in a wrongposition.

FIG. 4 shows the area of the reversing drum with the conveyor beltfolded in the upper and lower strands of the belt.

FIG. 5 shows the cross section of a tubular belt with embedded tie rods,as well as with two cameras monitoring the overlap area.

FIG. 6 shows the cross section of a tubular belt according to FIG. 5with one camera and an additional camera and an additional light source;and

FIG. 7 shows a tubular belt conveyor system as well as the operationalprinciple of the optoelectronic system working in conjunction with aprocess computer, a control for the guide rollers and a drive control.

The following list of reference symbols is applicable in connection withthe figures:

1 Tubular belt conveyor system

2 Tubular belt

3 Normal position of overlap area

4 Driving drum (loading drum)

5 Reversing drum (ejecting drum)

6 Wrong position of overlap area

7 Folded conveyor belt in upper strand

8 Folded conveyor belt in lower strand

9 Tie rod

10 Visible edge of tubular belt

11 Invisible edge of tubular belt

12 Optoelectronic system (digital line or area camera u, v, w)

13 Light source

14 Guide rollers

15 Process computer

16 Guide rollers control

17 Drive control

A Left side of belt in moving direction

B Right side of belt in moving direction

C Overlap area

X Closing of conveyor belt to form a tubular belt

Y Opening of tubular belt

Z Light beam

FIG. 1 shows the upper strand of a tubular conveyor belt system 1 wherethe material is conveyed. The driving drum 4 is at the same time theloading drum (material loading area) where the material is transportedin the direction indicated by the arrow. Within the area X, the conveyorbelt is closed by overlapping its longitudinal edges so as to form atubular belt 2, whereby the normal position 3 of the overlap is shown,i.e. the desired position. Within the area Y, the tubular belt 2 is thenopened again. On the reversing drum 5, which is at the same time theejecting drum (material unloading area), the conveyor belt changes intothe lower strand, forming there a tubular belt as well; however, withouttransporting any material.

Now, the optoelectronic system 12 (FIGS. 5 to 7) is preferably mountedin the area Y, notably on both the upper and lower strands of the belt.

FIG. 2 shows again the tubular belt 2 in the moving direction (directionof arrow) with the overlap in the normal position 3, forming a left beltside A and a right belt side B with a substantially symmetricalassociation.

Now, FIG. 3 shows a tubular belt 2 with the overlap in the wrongposition 6 in relation to the correct position 3, notably with a lateralshift of the overlap (=twisted belt) toward the left belt side A.

FIG. 4, furthermore, shows the possible consequences if the overlap isin the wrong position according to FIG. 3, whereby the longitudinaledges of the conveyor belt 7 and 8 are folded within the area of thereversing drum 5 in the upper and lower strands, which is undesirable.

According to FIG. 5, the tubular belt 2 is provided with a tie rod 9 inthe form of a multi-layer fabric. The overlap area C of the tubular belt2 extends in this connection from the visible edge 10 up to theinvisible edge 11.

The optoelectronic system 12 is formed by the two digital line or areacameras “u” and “v”, whereby particularly digital line cameras areemployed. The two cameras each are arranged laterally of the overlaparea C of the tubular belt 2 notably with respect to the normal position3 (FIGS. 1 and 2) of the overlap.

Now, if a wrong position 6 (FIG. 3) occurs, the optoelectronic system 12responds accordingly, which is explained later in the following inconnection with FIG. 7.

FIG. 6 shows the same tubular belt 2 according to FIG. 5 with theoverlap area C. In the present case, the optoelectronic system 12 in theform of one single digital or area camera “w” is substantially mounteddirectly above the visible edge 10 of the tubular belt, notably withobservation of the course followed by the edge and thus of the overlaparea C. An additional light source 13, of which the light beam Z issubstantially aligned in the direction. of the area of the visible edge10 of the tubular belt, supports the observation of the course run bythe edge or the overlap area C.

According to FIG. 7, the optoelectronic system 12 is coupled with aprocess computer 15, a guide roller control 16 and a drive control 17.Said overall system has the two following important functions:

(1) A signal conforming to the quantity of the deviation is transmittedby at least one camera “w” to the process computer 15, which controlsthe required corrective setting of one or more of the guide rollers 14of the conveyor system 1. Any migration of the overlap toward the leftor right side leads to counter-steering to the left or right side. Theguide roller control 16 as a compensating control is active until theoverlap is guided back into a programmed tolerance field recognized bythe camera “w”.

(2) If the overlap migrates out of a defined tolerance field, or ifcorrective measures fail to lead to success within a preset period oftime, the camera “w” generates an emergency signal leading to shutdownof the conveyor system via the process computer 15, notably inconjunction with the drive control 17.

Furthermore, it is advantageous if the optoelectronic system is equippedwith a device blowing it clear. The optics is kept clean in this manner.

What is claimed is:
 1. A device for monitoring a tubular belt conveyorsystem comprising: a conveyor belt made of elastomeric material withembedded tie rods, longitudinal edges, an open section and a closedsection wherein the longitudinal edges have a desired overlap to form atubular belt with an overlap area; a driving drum; a reversing drum;support rollers; guide rollers; and supporting structures; wherein saiddevice comprises an optoelectronic system mounted where the closedsection meets the open section for monitoring the overlap areacomprising at least one light source whose light beam is aligned withthe overlap area, said optoelectronic system, if deviation from thedesired overlap occurs, initiating a corrective setting by means of theguide rollers and, it the desired overlap does not occur within a presetperiod of time, effecting an automatic shutdown of the tubular beltconveyor system.
 2. A device for monitoring a tubular belt conveyorsystem comprising: a conveyor belt made of elastomeric material withembedded tie rods, longitudinal edges, an open section and a closedsection wherein the longitudinal edges have a desired overlap to form atubular belt with an overlap area; a driving drum; a reversing drum;support rollers; guide rollers; and supporting structures; wherein saiddevice comprises an optoelectronic system coupled with a processcomputer, a guide roller control and a drive control for monitoring theoverlap area comprising at least one light source whose light beam isaligned with the overlap area, said optoelectronic system, if deviationfrom the desired overlap occurs, initiating a corrective setting bymeans of the guide rollers and, if the desired overlap does not occurwithin a preset period of time, effecting an automatic shutdown of thetubular belt conveyor system.
 3. The device according to claim 1,wherein the optoelectronic system comprises at least one digital line orarea camera.
 4. The device according to claim 2, wherein theoptoelectronic system is mounted directly above the overlap area of thetubular belt.
 5. The device according to claim 4, wherein theoptoelectronic system is substantially mounted directly above a visibleedge of the tubular belt.
 6. The device according to claim 2, whereinthe optoelectronic system is mounted laterally of the overlap area ofthe tubular belt.
 7. The device according to claim 2, wherein the lightsource is mounted approximately above an invisible edge of the tubularbelt.
 8. The device according to claim 2, wherein the light beam of thelight source is substantially aligned in the direction of a visible edgeof the tubular belt.
 9. The device according to claim 1, wherein theoptoelectronic system is equipped with a compressed-air clearing device.